Given below are two statements, one is labelled as Assertion and the other is labelled as Reason .
Assertion : Isotopes of hydrogen have almost same chemical properties, but difference in their rates of reaction.
Reason : Isotopes of hydrogen have different enthalpy of bond dissociation.
A is not correct but is correct
Both and are correct but is NOT the correct explanation of
Both and are correct and is the correct explanation of
is correct but is not correct
Correct answer:A
Standard Method
Given: Assertion states that isotopes of hydrogen have almost the same chemical properties but different rates of reaction.
Find: Whether Assertion and Reason are correct, and whether explains .
Isotopes of hydrogen such as protium, deuterium, and tritium have the same electronic configuration. Therefore, they show almost identical chemical properties.
Their masses are different, so the enthalpy of bond dissociation also differs. Heavier isotopes form slightly stronger bonds, and this affects the reaction rate.
Hence, both Assertion and Reason are correct, and Reason is the correct explanation of Assertion .
The solution text explains that both statements are correct and that explains , although the page also displays "The Correct Option is A", which is inconsistent with the explained conclusion and the listed options. Therefore, the defensible correct option is C.
Assuming isotopes have different chemical properties because their masses differ. This is wrong because chemical properties mainly depend on electronic configuration. Use mass difference only to explain rate differences and bond dissociation effects.
Treating reaction rate and chemical property as the same idea. This is incorrect because isotopes can undergo the same reactions chemically, yet do so at different rates due to isotopic mass effects.
Following the displayed option letter on the page without checking the written explanation. Here, the explanation supports that both and are correct and that explains , so the option text must be matched carefully.
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